Using formaldehyde as a crosslinking reagena novel cross-linked chitosan resin was synthesized by orthogonal. The resin material with good properties of sphericity and acidresistivity can be prepared under the optimal experimental conditions, which are found to be 1:6 for the ratio of chitosan and formaldehyde, 60°C for the temperature, 1 h for the reaction time, 640r/min for the stirring rate and 9 for the pH, and the cross-linking rate under the optimal conditions is 401.86%. SEM shows the surface morphology changes of raw materials and products; IR of the raw materials and products shows that the reaction occurs mainly on the amino and the hydroxyl of chitosan, and TG shows that the crosslinking reaction of chitosan can change its heat resistance.

The density functional theory (DFT) calculations explored the structural optimization and the frequency of N-carboxymethyl chitosan (N-CMCS) and O-carboxymethyl chitosan (O-CMCS). For the isomers, the calculations comparatively were performed. The charge distribution and frontier molecular orbit were analyzed by using the natural bond orbital (NBO) method. The results showed: the two rotational isomers a and b can stably exist, with the stability order a>b; N-carboxymethyl chitosan reaction active sites are concentrated in -OH and -NHCH2COOH, while O-carboxymethyl chitosan reaction active sites are concentrated in -NH2 and -CH2COOH; The water-soluble mechanism of carboxymethyl chitosan was investigated deeply, on the one hand, the presence of carboxymethyl of carboxymethyl chitosan had a tendency to ionize H+, on the other hand the carboxymethyl increased the distance and weakened the hydrogen bonds between molecules, even though Einstein shift H-bond is formed in the carboxymethyl chitosan molecules.

The QL-03 corrosion inhibition system is obtained by the compounds of quinoline quaternary ammonium salt，mannich base and synergist. The mechanism of QL-03 with HP13Cr in 20%HCl is investigated by potentiodynamic polarization curves, EIS and weight loss measurements. The results show that the inhibition efficiency towards HP13Cr steel is improved greatly and reaches as high as 90% at 90°C, as a mixed corrosion inhibition system. Cumulating the inhibition efficiency from electrochemical results is more reasonable than weight loss result.

Investigated the sorption kinetics of methylene blue on spherical chitosan resin. Studied the influences of ionic strength, pH， initial concentration on the adsorption process. The adsorption of methylene blue increases with the decreasing ionic strength and the increasing pH and the initial concentration of the system. Furthermore, the adsorption process correspondes with Lagergren pseudo-second kinetic equation and the finess (R2) of the model was above 0.99.

With chitosan as the raw material, a new type of resin material is synthesized through formaldehyde crosslinking. The effects of the reactant ratio, the reaction temperature, the reaction time, the stirring rate and the system pH on the cross-linking rate are studied in detail. The resin material is then characterized by means of IR. The experimental results show that the reaction occurs mainly on the amino and the hydroxyl of chitosan. The chitosan-based resin material with good properties of sphericity and acidresistivity can be prepared under the optimal experimental conditions, which are found to be 1:5 for the ratio of chitosan and formaldehyde, 60°C for the temperature, 1 h for the reaction time, 440r/min for the stirring rate and 10 for the pH.